Charmed S3 Ep 13 - Gender Transformations

Season 3 Episode 13 Bride And Gloom
When Piper leaves, Zile assumes her form and asks Prue for some lipstick. He then resumes his true form and blinks back to his lair. Just as Piper is about to get Prue a "divorce" by freezing Zile, he shapeshifts, assuming Prue's form. The two both blink so they have Piper and Phoebe surrounded. Piper and Phoebe can't tell which is the real Prue. Prue tells Zile that she loves him, and Zile replies, "You too." Phoebe remembers that Cole told her evil can't love. Dantalian conjures giant daggers into Prue and Zile's hands, and they go in on Piper and Phoebe. Phoebe urges Piper to freeze Zile. Piper obliges, and then shatters him.